Photographic exposure apparatus

ABSTRACT

A portable photographic exposure apparatus for making reproductions of loft drawings, body drafts or the like in which a film and drawing are fed simultaneously into the exposure area. The apparatus includes a wheeled cabinet structure, which may include an internal supply of film, and an exposure unit secured to the cabinet and including a source of light and a source of static electricity. Static electricity is used to press the film and drawing together and smooth the drawing against the film for dimensional accuracy of the reproduction and to eliminate air bubbles. The exposed film and drawing may be separated and the film fed to a developer which may be attached to or positioned adjacent the cabinet structure.

t V 1 i United States Patent 1 1 1111 3,814,519 Zeunen et al, I 1 June 4, 1974 [54] PHOTOGRAPHIC EXPOSURE APPARATUS 3.318.213 /1967 Kowalski 355/14 3. 55' [75] Inventors: Barthel Zeunen, Cla'rkston; Rex C. wise-3g Grace, Troy; Alvie R. Dunn, FOREIGN PATENTS OR APPLICATIONS Madison Height-S, all Of Mich. 550.217 5/1932 Germany 355/118 [73] Assignee: Capitol Reproductions Inc., Madison Heights, Mich Primary Exammer-John M. Horan I Attorney, Agent, or Firm-Hauke, Gifford. Patalidis & [22] Filed: Dec. 29, 197] Dumom [2]] Appl. No.: 213,398

1 v [57] ABSTRACT I A portable photographic exposure apparatus for mak- [fi] mg reproductions ofloft drawings, body drafts or the 93 97 99 like in which a film and drawing are fed simulta- I 0 g h jneously into the exposure area. The apparatus includes a wheeled cabinet structure, which may include an internal supply of film, and an exposure unit se- [56] References cued cured to the cabinetand including a source of light UNITED STATES PATENTS and a source of static electricity. Static electricity is 1,682,979 9/1928 Oiler; 355/103 used to press the film and drawing together and 1.804.739 5/1931 Bru nkm. 355/103 smooth the-drawing against the film for dimensional $403,310 9/19)v Hassler 355/103 accuracy of the reproduction and to eliminate air bub- 3' 12/ 2. bles. The exposed film and drawing may be separated I and the film fed to a developer which may be attached ..,627.203 2/l953 Hessert 1. 355/64 d d. th t t t 2,719,714 /1955 Pratt 355/66 Posmone m e C4 me 5 2,849,9l6 9/l958 NOlllll 355/64: 6 9 Drawing Figures 3,194,]3l 7/1965 Robinson 5/3 A 52 v J r I 1 a 32 po 8 40 l .r/ 5 I "z 90 92 1 as 4 I 53 3o PAIENTEnJun 41914 3814.519

INVENTORS BARTHEL ZEUNEN REX c. GRACE ALVIE R.DUNN

f ftyJ PATENTEDJUN 4 I974 3.8 14.51 9

sumanra INVENTORS F/5 4 BARTHEL ZEUNEN REX c. GRACE ALVIE R. DUNN 5ATENTEDJUN 4 m4 SHEET 3 (IF 4 53 INVENTORS BARTHEL ZEUNEN REX c. GRACE ALVIE R. DUNN B Y M g m wwa FIG-8 INVENTORS BARTHEL ZEUNEN REX C. GRACE ALVIE R. DUNN BY M M/wqf BACKGROUND OF THE INVENTION I. Field of the Invention This invention relates to improvements in portable photographic exposure apparatus of the type generally used to expose large sheets of film which are fed into the apparatus along with large loft drawings, body drafts and the like for making accurate photographic reproductions, and to the type of exposure apparatus which may readily be moved relatively close to the area where the drawing is being prepared. This invention relates more specifically to the type of exposure apparatus which may make photographic reproductions of vir tually any length and which uses electrostatic processes for adhering film to a drawing during exposure.

II. Description of the Prior Art In the reproduction of large, synthetic sheet loft drawings and, body drafts, it is customary to ship the completed drawings to a different facility for photographic processing to make the necessary reproductions, and 'the shipping and handling for purposes of making reproductions is a relatively expensive process. Furthermore, there is the concomitant risk of damage and the possibility of temperature and humidity changes causing distortions. This is inadmissable where very accurately dimensioned drawing reproductions are a necessity.

Portable exposure apparatus which may readily be moved into the area wherein the drawing is initially prepared have been proposed heretofore, as in U. 5. Pat. No. 3,723,001 for Photographic Exposure Apparatus," issued Mar. 27, 1973, of common inventorship and ownershipiherewith, which discloses an apparatus for making film exposure directly from a drawing on a drawing board. The present invention contains several improvements over the apparatus described in that ap-, plication and, furthermore, may be used to reproduce drawings of indefinite length without requiring their positioning-on the drawing board.

SUMMARY OF THE INVENTION thus the drawings to be reproduced may be of virtuallyany length, and may consist of commercially available material, such as polyester film or other similar dimensionally stable material having a light sensitive coating thereon to provide a reproduction when exposed under (or over) the drawing.

Such film lends itself to being pinned to the'drawing -by an electrostatic charge which, according to the present invention, is projected from an electrode carried directly by the exposure unit. The electrode is arcuate to smooth the drawing to the film from the center outwardly to the edges and to eliminate air spaces therebe tween.

DESCRIPTION OF THE DRAWINGS The present invention, its objects and advantages, will become apparent upon reading the following detailed description in conjunction with the accompanyingdrawings, wherein like reference characters refer to like parts throughout the several views, and in which:

FIG. 1 is a perspective view of a preferred photographic exposure apparatus embodying the principles of the present invention;

FIG. 2 is a side elevational view of the apparatus according to the present invention and includes an optional processing unit coupled to the exposure apparatus for continuous photographic film exposure and reproduction;

FIG. 3 is a front elevational view of the apparatus of FIG. 1 illustrating part of the feeding means ofthe present invention; I

FIG. 4 is a rear elevational view illustrating a roller assembly for removing the exposed film and drawing from the film exposure apparatus;

FIG. 5 is a cross-sectional view taken substantially on the line 5-5 of FIG. 3, illustrating the film and drawing feed and exposure means of the present invention;

FIG. 5A is a fragmentarycross-sectional view of a portion of the apparatusillustrating a modification of some components thereof;

FIG. 6 is an enlarged fragmentary crosssectional view illustrating the electrostatic discharge apparatus embodied in the present invention;

FIG. 7 is a top plan view, partially broken away, of the exposure apparatus of the invention; and

FIG. 8 is a fragmentary cross-sectional view of the exposure apparatus of the present invention taken substantially along line 8-8 of FIG. 7.

DETAILED DESCRIPTION OF THE INVENTION FIGS. 1 through 5 illustrate a preferred photographic exposure apparatus 10 of the present invention, comprising asupport unit or cabinet 12 and an exposure unit l4 located on top of the cabinet 12. As indicated in FIG. 2, a drawing 16 to be copied, together with a blank film 18 to be exposed, are fed through the exposure unit 14 with the drawing preferably on top and of translucent material such as polyester or the like. The maximum length of the drawing 16 whichmay be copied is, for all intents and purposes, limited only by the available length of blank film, which'may be supplied from a roll stored in the frontend of the cabinet 12.

The cabinet 12 is a generally rectangular structure having'vertical side walls and end walls which slope vertically upward and outward, and includes vertical corner posts 20 and casters 22 to permit the entire apparatus to be transported at will, or if desired to be moved adjacent to a table where the drawing is being prepared. The cabinet 12 includes a flat top or expo sure platform 24, seen in FIG. 5, across which the film 18 and drawing 16 are moved during exposure of the film. The platform 24 is of substantially the same width as the cabinet 12, but somewhat shorter in length to accommodate within the cabinet 12 the film and drawing feed means as will be explained hereinafter.

A plate 26, which may be hinged to the shelf 28, is provided at the front of the cabinet 12 (the right side as viewed in FIG. 5). The plate 26 may be lowered or 7 opened from the front of the cabinet 12 until restrained by chains 30. A supply of blank film 18 may be stored on the shelf .28.

A work area 32 is disposed above the shelf 28 where an operator may align the film and drawing prior to inserting them into the exposure unit 14, and a'control panel 34 may be conveniently installed, as shown,

above the work area 32.

A shaft 40 is located behind the control panel 34 and journaled in side walls 36 and 38 of the cabinet 12. The shaft 40 supports a feed roller 42, extending outwardly beyond the platform 24. The film and the drawing are inserted beneath the feed roller to be fed into the exposure unit 14.

The cabinet 12 includes means to feed the film and drawingsimultaneously through the exposure unit 14.

Specifically, two rollers 44 and 46 are journaled into the side walls 36 and 38 of the cabinet 12; one roller 44 at the rear of the photographic exposure apparatus and the other roller 46 at the front. The rear roller 44 is preferably driven by a belt 50 from a motor 48 carried within the cabinet 12 in any convenient location as shown.

An endless conveyor belt5 2 encompasses the two rollers 44 and 46, its upper run portion overlying the platform 24, with the roller 46 underlying the feed roller 42. As the motor 48 drives the rear roller 44, the conveyor belt 52 travels around the rollers. The conveyor belt 52 should be of a width sufficient to provide support for the film and drawing; however, the wider the conveyor belt, the more likely there is to be some slippage and stretching, which is compensated for by a tension and tracking means, illustrated in FIG. 5 as including a roller 54, which is mounted to the cabinet 12 for vertical adjustment of the ends (only one end shown) between two support members 56 and 58 by screws 60 threaded to the roller 54 and adapted to move the ends of the roller vertically upward or downward to respectively decrease or increase the belt tension. By adjusting both threaded screws, the overall r tension in the conveyor belt 52 may be increased or decreased, and by changing the-tension of one side of the belt 52 relative to the other side the alignment of the film and drawing may beregulated for proper tracking through the exposure unit 14.

Referring to FIGS. .5 and 6, atthe front or leading end of theexposure unit 14, a housing 62, having an open bottom. shields and supports an electrostatic discharge barassernbly 64, which includes metal supports 66 secured to the housing 62 by conventional means such as screws 68. The assembly '64 extends across the width of the exposure unit 14 and is slightly arcuate, as shown in FIG. 7, with both ends of the assembly 64 being bowed toward the rear of the apparatus, leaving the center closer to the front, or feed, end.

The assembly 64 consists ofa dielectric material tube 70 carried by the supports 66 and encompassing an electrode 71, from which a series of discharge pins 72 project vertically downward. The pins 72 are maintained in vertical alignment 'by an insert 74 which is preferably made of plastic or other dielectric insulating material. When current is supplied to the electrode 71 from a suitable power supply and when the film and drawing are passed beneath the pins 72, they discharge an electrostatic flux field along the leading edge of the exposure unit 14, which produces an electrostatic charge between the film, drawing and belt. Thus, the film l8 and the drawing l6'are attracted to each other and also to the conveyor belt 52.

Since the electrode 71 is slightly arcuate, the electrostatic charge is directed first at the center and then progressively toward the side edges, so that the film and drawing will be smoothed out and spread toward their side edges, making for complete contact between film and drawing which is essential for accurate reproduction, and eliminating any air bubbles which might otherwise be trapped in between.

Referring to FIGS. 5, 7 and 8, the exposure unit 14 comprises a generally rectilinear housing structure having an open bottom, side walls 78, end walls 80 and a top comprising two members 82 and 84, which are preferably hinged together as at 76 along a transverse center line. The two top members 82 and 84 rest on the side walls 78 and are adapted to be raised, as indicated in FIG. 5, to provide access from both ends 80.

The side walls 78 are adapted to support a series of exposure lamps 86 which may be fluorescent tube lights, and which are disposed within the structure 76 to provide substantially uniform lighting therein for proper exposure of the film moving along the endless belt 52. The exposure unit 14 may be provided with a motor driven fan 88 (FIGS. l-4) adapted to discharge cooling air across the exposure lamps 86 to prevent their overheating and further to prevent their heat from affecting the drawing and film being exposed.

A plate 90 of glass or other transparent material is disposed beneath he exposure lamps 86 and operates to exert downward pressure on the film and the drawing advancing through the exposure unit to keep them in flat registry. Studs 92, at either side of the front edge of the plate 90, support and maintain it sufficiently above the exposure platform 24 and conveyor belt 52 to permit the film l8 and drawing 16 to be initially inserted beneath the plate 90. This may best be seen in the illustration of FIG. 8. In addition, it may be desir able to provide additional support at the center of the front plate edge to prevent sagging which might otherwise block entry of the film and the drawing. As seen best in FIG. 6, attached to the center of the front end wall 80 is a bracket 94 to which one end of a screw 96 wall 80 and an end of an arm 100 is pivotably attachedto each angle bracket 98 with theother end of each arm 100 secured by a spring 102 to the frame of the exposure unit 14. A shaft 104 passes through holes in the arms 100 to support rollers 106 disposed adjacent the arms 100. Since each arm 100 is pivoted and spring biased, the rollers 106 are urged generally downwardly.

- A vertical slot 108 is located in each side wall 78, slightly below the level of the angle brackets 98, and a long shaft 110 is journaled in the slots 108 to carry a large roller 112. The three rollers 106 are thus spring biased against'the large roller [12 to urge it downwardly against the underlying rear conveyor belt roller 44 as seen in FIG. 5, to not only maintain movement of the film l8 and drawing 16 with the conveyor belt 52 but to hold the belt 52 against its drive roller 44 to avoid slippage which might mar the lower surface of the film 18 or cause erratic movement of the film and drawing through the apparatus.

FIG. 5A illustrates a modified construction which may be used for the foregoing purpose. In this modification, the rollers 106 with their associated parts are eliminated. The roller 112 is journaled in a verticalslot 113a provided in a pair of carrying brackets 113 at the ends of the roller 112 (only one bracket being shown),

' the weight of the roller 112 being sufficient to hold the film l8 and drawing 16 against the belt 52 which is driven by the drive roller 44. To ensure that the belt 52 does not slip on its driver roller 44, a pair of idler rollers 45 and 47 are positioned with the belt'52 wrapped around them as shown. The roller 45 is disposed close to and on a horizontal line substantially level with the roller 44 so that the belt makes a maximum available peripheral contact with the roller 44. When the previously described roller 54 (FIG. 5) is adjusted to apply tension to the belt. it will thus be pulled tautly around the roller 44.

To operate the exposure apparatus, one end of the blank film 18 may be pulled from the shelf 28 around the front of the exposure unit 14 to the work area 32. The leading end of the drawing is placed on top of the film and both are inserted together between the roller 42 and the conveyor belt 52, which advances the film and drawing together through the exposure apparatus.

As the film and the drawing pass under the discharge pins 72 of the electrode 71, the-electrostatic discharge adheres the drawing, the film, and the conveyor belt, which pass beneath theplate 90 and under the exposure lamps 86 to expose the film. The duration of exposure is controlled by the speed of the conveyor belt 52, which may be monitored and changed by varying the speed of the conveyor drive motor 48. Light quantity may be varied by selectively controlling the number of exposure lamps energized.

At the rear of the exposure unit 14 it is desirable to dissipate the electrostatic charge and separate the exposed film 18 from the drawing 16. The large movable roller 112 is preferably metallic and grounded by contact through its shaft 110 to the side walls of the apparatus to dissipate the electrostatic charge. The film and the drawing may then be separated. Optionally, a guide (not shown) having a beveled edge may be positioned behind the roller 112 to separate the film from the drawing.

Referring to FIG. 2, a processing unit 114 may be adapted for coupling directly to the reproduction apparatus l0, and may include a horizontal beveled edge bar 116 for separating the film from the drawing. The film may then be fed directly into the apparatus 114 for continuous processing through exposure to developing, and the drawing may be readily removed from the processing unit. a

It is apparent that all of the operating units of the apparatus 10, such as the conveyor belt drive motor 48, the electrostatic system, the exposure lamps 86, and blower 88, are connected by suitable electrical circuitry (not shown) to the control panel 34. Also, if desired, the belt tensioning and tracking may be electrically or otherwise operated from the control panel 34, or even may be automatically controlled by use of any devices known in the art.

The described apparatus is only considered as preferred and illustrative of the inventive concept and as such is not to be considered as restricting the scope of the invention. Various arrangements, changes and modifications may be made by those skilled in the art without departing from the spirit of the invention or the scope of the appended claims.

What is claimed is:

1. An apparatus for making a direct photographic reproduction from a loft drawing or the like comprising:

a support platform; means for simultaneously advancing a continuous sheet of film and said drawing over said platform;

an exposure unit mounted in fixed relationship to said platform and comprising a light source;

a transparent plate overlying said platform and exerting a downward force to hold the film and drawing together against said platform during exposure;

control means for energizing said light source and said feeding means for progressively exposing said film; and

a plurality of studs for spacing a leading edge of said transparent plate above said support platform to permit said film and drawing to pass therebeneath.

2. The apparatus as in claim 1 wherein said light source comprises a plurality of elongated lights disposed to provide substantially uniform lighting throughout said exposure unit.

3. The apparatus as in claim 1 wherein said exposure unit includes a cover. hinged transversely at the center, for providing front and rear access to said exposure unit.

4. The apparatus as in claim 1 and including a first roller at the opposite end of said unit platform from the end thereof over which the film and drawing are first advanced for contacting said film and drawing after exposure.

5. The apparatus as in claim 4 wherein said first roller is mounted for vertical movement, and further including a second roller above and contacting said first roller and urging same downwardly into engagement with the uppermost of said film and drawing.

6. The apparatus as in claim 4 wherein said means for advancing said film and drawing includes a continuous conveyor belt extending around a second roller positioned beneath said first roller with the film and drawing being held by said first roller on the top run of said belt over said second roller, and a third roller being positioned closely adjacent and on a substantially common horizontal line with said second roller, the lower run of said conveyor belt extending over said third roller to thereby maintain said belt in maximum available peripheral contact with said second roller, and motor meansdriving one of said rollers. 

1. An apparatus for making a direct photographic reproduction from a loft drawing or the like comprising: a support platform; means for simultaneously advancing a continuous sheet of film and said drawing over said platform; an exposure unit mounted in fixed relationship to said platform and comprising a light source; a transparent plate overlying said platform and exerting a downward force to hold the film and drawing together against said platform during exposure; control means for energizing said light source and said feeding means for progressively exposing said film; and a plurality of studs for spacing a leading edge of said transparent plate above said support platform to permit said film and drawing to pass therebeneath.
 2. The apparatus as in claim 1 wherein said light source comprises a plurality of elongated lights disposed to provide substantially uniform lighting throughout said exposure unit.
 3. The apparatus as in claim 1 wherein said exposure unit includes a cover, hinged transversely at the center, for providing front and rear access to said exposure unit.
 4. The apparatus as in claim 1 and including a first roller at the opposite end of said unit platform from the end thereof over which the film and drawing are first advanced for contacting said film and drawing after exposure.
 5. The apparatus as in claim 4 wherein said first roller is mounted for vertical movement, and further including a second roller above and contacting said first roller and urging same downwardly into engagement with the uppermost of said film and drawing.
 6. THe apparatus as in claim 4 wherein said means for advancing said film and drawing includes a continuous conveyor belt extending around a second roller positioned beneath said first roller with the film and drawing being held by said first roller on the top run of said belt over said second roller, and a third roller being positioned closely adjacent and on a substantially common horizontal line with said second roller, the lower run of said conveyor belt extending over said third roller to thereby maintain said belt in maximum available peripheral contact with said second roller, and motor means driving one of said rollers. 